Tissue antigens in seminal secretions. I. Precipitin reactions of rabbit antiserum to human seminal plasma.

Precipitating antibodies prepared in rabbits with human seminal plasma (HSP) have been used in a preliminary study to define the antigenicity of HSP by use of gel precipitin methods. Also, a method for evaluating and preserving liquid precipitates of acid phosphatase in polyacrylamide is described. Some ten or eleven antigens were demonstrated by Ouchterlony agar immunodiffusion (ID). Eight of these appeared to be HSP-specific and two or three were also found in normal human serum (NHS). Five of the HSP-specific antigens were shown by agar immunoelectrophoresis (IEP) and by ID to be acid phosphatase. Four of these constituted the basic isoenzyme pattern and were shown by IEP and ID to be shared by prostatic fluid (HPF). Titration of HPF by ID yielded antigen titres of 46, 33, 17 and 3 for the four isoenzymes. IEP patterns obtained with HSP and HPF showed two isoenzymes migrating to the alpha-globulin zone. The third isoenzyme migrated to the alpha-2-fast beta area, while a fourth was seen as a slow beta precipitin arc formed consistently by HPF, and variably by HSP. HSP contained a fifth isoenzyme which also migrated to the slow beta area. Human prostate extract (HPE) showed only two, sometimes three, of these components, one of the slower components being frequently faint in appearance or absent. In HSP and HPF isoenzyme migrating to the alpha-2-fast beta zone exhibited two distinct characteristics: biphasic migration and limited diffusion, suggesting a heterogeneous high molecular weight isoenzyme or an isoenzyme complex. However, observed differences between HSP, HPF and HPE in migration rate, relative concentrations of subfractions, lateral diffusion, etc. leave open the question of the nature of the heterogeneity.